Refrigeration method and apparatus



1936. R. T. PALMER REFRIGERATION METHOD AND APPARATUS FOR THE CONDITIONING OF AIR MuJOou $N z A EEEEQE Filed July 16, 1935 Patented July 21, 19363 REFRIGERATION METHOD AND APPARATUS FOR THE CONDITIONING OF AIR- Robert T. Palmer, Sharon, Mass., assignor to B. F. Sturtevant Company, Inc., Hyde Park, Boston, Mass.

I Application July 16, 1935, Serial No. 31,597

9 Claims. (01. 62-476) UNlTED STATES PATENT OFFICE This invention relates to refrigeration methods and apparatus for the conditioning of air.

In those air conditioning systems such as are installed in motion picture theatres, where in summer the air is chilled to a low temperature, in order that the necessary dehumidification may take place, it is customary 'to mix recirculated air from the space being served with fresh outside air; to chill the mixture in a dehumidifier 10 to a temperature lower than the dew point of the air within the space and to mix variable quantities of by-pass recirculated air with the dehumidified fresh and recirculated air for the purpose of adding the necessary sensible heat to the too cold dehumidified air.

According to this invention, recirculated air only, passes through the dehumidifier and the necessary outside make up air passes through a cooler which does not cool the outside air to a temperature below the dew point of the recirculated air but merely cools the outside air to a condition approximately equal to that of the recirculated air. This cooled outside air mixes with the by-pass air at the output side of the dehumidifier and serves with'the by-pass air to raise the sensible heat of the too cold dehumidified .recirculated air.

According to a feature of this invention, the refrigerant used in the dehumidifier for dehumidifying the recirculated air is circulated through the cooler for cooling the outside make up air before being recooled in the refrigeration apparatus. The refrigerant in a single circuit thus serves, efiiciently to dehumidify the recirculated air and to cool the outside air to a condition approachingthat of the recirculated air.

The outside air is not dehumidified by being cooled to a temperature below the dew point of the indoor air since the refrigerant which is used to cool the outside air was previously heated in the dehumidifier to a temperature above the dew point temperature of the recirculated air. An object of the invention is to dehumidify recirculated air from the space to be served and to mix with the dehumidified air, outside air cooled to a temperature approximating that of the air within the space to .be served.

Another object of the invention is to dehudify recirculated air from the space to be 5Y served, and to mix with the dehumidified recirculated air, by-pass recirculated air and outside air cooled to a condition approximately that of the by-pass air.

Another object of the invention is to dehu-- 65 midify L with refrigeration, recirculated air from the suction of the fan I through the duct 8 and 15 through the dehumidifier 5. The dehumidifier is supplied with chilled waterthrough the pipe 8 from the evaporator III which chills the spray water to a sufliciently low temperature so that the recirculated air passing through the dehumidifier g9 has its temperaturereduced to the required dew point. The dehumidifier is preferably operated under the well known dew point control, for the adjustment of the spray water temperature.

The dehumidifier 5 is so constructed and ar- 25 ranged that the spray water leaving it through the pipe ll, takes on in the dehumidifier, a temperature above the dew point temperature of the recirculated air.

The spray Water on leaving the dehumidifier 3o 5 passes through the pipe ll into the spray type outside air cooler l2 and acts to cool the outside air which enters through the duct l3 to a temperature above the dew point of the recirculated air which passes as by-pass air through the duct 35 M to be mixed at the output side of the dehumidifier 5 with the air leaving the. dehumidifier.

The cooled outside air leaving the cooler I2 mixes with the air leaving the dehumidifier and with the by-pass air and having substantially 40 the temperature of the by-pass air, acts with the by-pass air to raise the sensible heat of the air leaving the dehumidifier.

The by-pass and partially cooled outside air acts to increase the sensible heat of the air leav- 45 ing the dehumidifier 5, under control of the thermostat, exposed to conditions within the enclosure 6. The thermostat l5 also acts to control the volume of air passing through the dehumidifier as when the load within the enclosure 6 changes.

When the enclosure 6 is empty, minimum cooling and dehumidification is required due to the absence of occupants who would add both moisture and sensible heat to the air. The thermostat l5 which may be responsive to wet or dry bulb temperature or both, then acts to open motors l9 and 20.

With the damper l6 moved towards open position and the damper I] moved simultaneously towards closed position, the volume of air through the by-pass duct l4 increases towards a maximum and the volume of recirculated air through the dehumidifier 5and the volume of outside air through the outside air duct I3 and the cooler l2 decreases towards a minimum with the result that minimum refrigeration is required.

When on the other hand, the load within the enclosure 6 increases, the thermostat l5 causes the damper Hi to be adjusted towards closed po sition and the damper 11 to be adjusted towards open position. This results in increased fiow of recirculated air through the dehumidifier 5 and of outside air through the duct l3 and cooler I21 and decreased flow of air through the by-pass duct l4.

Upon decrease of by-pass air there is an increase of outside air for adding sensible heat to outside air'passing through the cooler l2 willv cause a change in the dew point of the air entering the enclosure 6. While this may not be objectionable where the system is used for the comfort conditioning of air, it perhaps mightbe objectionable for the industrial conditioning ofair-in certain plants where conditioned air at a constant dew point is required. To ensure such a constant dew point, the dew point control 26 is mounted in the duct 2! on the delivery side of the ducts M, 28, and 29, and acts for example, to control the supply of electrical energy to the motor 30 driving the compressor 3|.

When under unusual conditions, the necessary reheating of the chilled air is not accomplished by the mixture therewith of the by-Pa and out side air, the thermostat 2| acts to permit the flow of steam from the steam source 22 into the reheater coils 23 by adjustment of the electrically controlled valve 24.

The steam coils 23 and the similar steam coils 25 in contact with the outside air may be used in cold weather for heating the air supplied to the enclosure 6 at which time the cooler l2 and dehumidifier 5 or both may be used for-adding the necessary moisture to the air. I

The apparatus is illustrated diagrammatically by the drawing and there has been no attempt to illustrate all of the equipment obviously required. For example, means for forcing water not be limited to the exact arrangement described, as many departures may be made by those skilled in the art after having had access to this disclosure.

What is claimed is:

1. Refrigeration apparatus for the conditioning of air comprising in combination,,an enclosure, the air of which is to be conditioned, a dehumidifier, means for withdrawing air from said enclosure and for passing a portion thereof through said dehumidifier and for passing another portion thereof as by-pass air to the output side of said dehumidifier, a cooler, means for passing outside air through said cooler, means for mixing the air passing from said dehumidifier, the bypass air and the outside air leaving said cooler and for supplying the mixture within said enclosure, means for circulating a refrigerating fluid through said dehumidifier, and means for circulating the refrigerating fluid leaving said dehumidifier through said cooler.

2. Refrigeration apparatus for the conditioning of air comprising in combination, an enclosure, the air of which is to be conditioned, a dehumidifier, means for withdrawing air from said enclosure and for passing same through said dehumidifier, a cooler, means for passing outside air through said cooler, means for mixing the air passing from said dehumidifier, and the outside air leaving said cooler and for supplying the mixture within said enclosure, means for cir- 3 culating a refrigerating fluid through said dehumidifier, and means for circulating the refrigerating fluid leaving said dehumidifier through said cooler.

3. Refrigeration apparatus for the conditioning of air comprising in combination, an enclosure, the air of which is to be conditioned, means for withdrawing air from said enclosure, :3. dehumidifier for chilling a portion of said withdrawn air to a temperature lower. than the dew point of the air within said enclosure, means for passing another portion of said withdrawn air as by-pass air to be mixed with said other portion after it has been chilled, means for cooling outside air to a condition nearer to that of said by-pass air than to that of said chilled air, and means for mixing said chilled air, said by-pass air and said cooled outside air at the output side of said dehumidifier and for supplying the mixture into said enclosure.

4. Refrigeration apparatus for the conditioning of air comprising in combination, an enclosure, the air of which is to be conditioned, a dehumidifier, means for withdrawing air from said enclosure and for passing a portion thereof through said dehumidifier and for passing another portion thereof as by-pass air to the output side of said dehumidifier, a cooler, means for passing outside air through said cooler, means for mixing the air passing from said dehumidifier, the by-pass air and the outside air leaving said cooler and for supplying the mixture within said enclosure, means for circulating a refrigerating fluid through said' dehumidifier, means for circulating the refrigerating fiuid leaving said dehumidifier through said cooler, and means for varying the proportion of by-pass air to outside air anddehumidified air as the load within said enclosure varies.

5. Refrigeration apparatus for the conditioning of air comprising in combination, an enclosure, the air of which is to be conditioned, a dehumidifier, means for withdrawing air from said enclosure and for passing samethrough said deair through said cooler, means for mixing th air passing from said dehumidifier, and the outside air leaving said cooler and for supplying'the mixture within said enclosure,'means' for circulating a refrigerating fluid through said dehumidifier, means for circulating the-refrigerating fluid leaving said dehumidifier through said cooler, and means for varying the proportion of outside air to deh umidified air as the load within, said enclosure varies. 6. Refrigeration apparatus for the conditioning of air comprising in combination, an encl'o sure, the'air of which is to be conditioned, a dehumidifier, means for withdrawing vair from said enclosure, means for chilling a portion of said withdrawn air in said dehumidifier to a temperature lower than the dew point of the air within- 26 said enclosure, means for passing anotherportion of said withdrawnair. as by-pass air to be mixed at the output side of said dehumidifier with said other portion after it has been chilled, means for cooling outside air toa condition nearer-to that of saidby-pass air than to that of said chilled air,'means for passing said cooled outside air to the output side of said dehumidifier'to be mixed with said chilled air and said -by-pass air and for supplying the mixture into said enclosure, and means for varying the volumes of by-pass air, of outside air and of dehumidified air asthe load within said enclosure varies, y 7. Heat exchange apparatus for the conditioning of air, comprising in combination, an enclosure, the'air of which isto be conditioned, means for withdrawing air from said enclosure and for chilling it to a temperature lower than the dew v "2,048,1 1 humidifier, a cooler, means for passing outside side air and of dehumidified air point or the air within said enclosure, meansfor cooling outside air to a conditionnearer to that of the air within said enclo'surethan to that of said chilled withdrawn air, means for mixing said .chilled withdrawn .air and said cooled outside air 5 and for supplying the mixture into said enclosure, and means for varying the volumes of outas the load within said'enclosure-varies. t 8. The method oi conditioning the air supplied toan enclosure which comprises recirculating air from the enclosure, chilling the recirculated air to a temperature, below the dew point, ofthe air withinsaid enclosure, cooling outside air to a condition nearer that of the air within said'enclosure than to that of the dehumdified air, mixing the cooled outside air and dehumidified air and supplying the mixture into saidenclosure, and varying the volumes ofrthe recirculated air and of the outside air as the load within said 20 enclosure changes.- a f 9. The method of conditioning the air supplied to an enclosure which comprises recirculating air from the enclosure, dividing the recirculated air into two streams, chilling the' air in one stream 25 V to a temperature below the dew point of the air" 'within said enclosur'e, cooling outside air to a condition nearerto that-of the .air in said enclosure than to that of the chilled air,-mlxing the chilled air, theairinf said otherfstream and the 30 cooled outside air and supplying thepmixture within said enclosure, andvarying the volumes of untreated recirculated air and that of the 'l chilled recirculated air andof-the outside the load withinsaid enclosure changes'.,

, ROBERT 'r. PALMER. 

